van den beld



c. M. B. VAN .D EN BELD. SIGHTING 0F GUNS.

APPLICATION FILED JAN. l0, I917- 1 ,31 ,401, PatentedSept. 16,1919.

k 3 SHEETSSHEET 2.

wfl'mwmz v fg go z 7W, 6&6 6;: 0%.?1 Vail java 12, wa w I AZ/ (attorney.

C. M. B. VAN DEN BELD.

SIGHTING 0F GUNS.

APPLICATION FILED JAN. I0. 1917.

1,316,401. PatentedSept. 16,1919.

3 SHEETS-SHEET 3.

Zmtnwow: 5

mawwg s vermt.B. van den Be Zd CASPER MELCI-IIOR BALTHAZAR VAN DEN BELD, or 'IIILLBURG, NETHERLANDS.

SIGHTING OF GUNS.

Application filed. January 10, 1917. Serial No. 141,681.

To all whom it'may concern: I

Be 1t known that I, CASPER MELCHIOR BALTHAZAR VAN DEN BELD, subject of the.

Queen of the Netherlands, residing at Tilburg, Kingdom of the Netherlands, have invented certain new and useful Improvements Relating to the Sighting of Guns, of which the following is a specification.

The present invention relates to improvements in sighting devices for ordnance, and more especially for anti-aircraft guns.

The primary object of the invention is to provide novel and improved sighting means whereby the pointing of the gun may be accomplished quickly and accurately, taking into account the altitude, range and speed of the target, the diminishing velocity of the projectile, and the influence of gravity on the projectile as varied by the different an gles of elevation of the gun. 7

Another object of the invention is to provide sighting means which is so con.-

constructed and related to the gun that con-.

tinuous sighting may be had by the observer without being disturbed by the firing of the gun.

To these and other ends, the invention consists in certain improvements, and combinations and arrangements of parts, all as will be hereinafter more fully described, the novel features being pointed out particularly in the claims at the end of the specification.

In the accompanying drawings:

Figure 1 is a side elevation of an antiaircraft gun equipped with sighting mechanism constructed in accordance with the present invention.

Fig. its sighting mechanism as shown in Fig. 1.

Fig. 3 is a rear elevation of the rear sight slide detached from its mounting.

Fig. 4 is a detail view of the rear portions of the sight support and gun cradle, showing means for adjusting the sighting device in accordance with different elevations of the target.

Fig. 5 is a diagrammatic plan view representing the field of vision of the eye of the observer in using the sighting device.

Fig. 6 represents a side elevation of the different fields of vision, one corresponding to a target in zenith, and the other two corresponding to targets at diiierent angles of elevation.

Fig. 7. is a diagrammatic view representing the sight-ring and the sight Plate on a 2 is a front view of the gun and larger scale, the distance between them being shortened.

r 1g. 8 1s a plan View of the sight-ring. I

Fig. 9. is a diagrammatic view representing the angle of variation between the elevation of the gun and the angle of devia tion ofthe projectile as affected by different elevations of the gun.

Fig. 10 isa'diagrammaticview showing a methodlof determining the calibrations ofthe scales represented in Fig.4 to allow for different ranges of the target. v I

Similar parts are designated by the same.

reference characters in the several views. The drawlng (Fig. 1) shows a gun Specification of Letters Patent. Patented Sept, 16,1919, I

equipped with a sighting device constructed I in accordance with the present invention, the dotted lines representing the position of the gun and sighting device when adjusted for one elevation, and'the full lines repre senting the position of the gun and its sighting device when set for another elevation.

The gun, the barrel of which is designated 4, is pivoted on a horizontal axis 5.-5 and the gun support is pivoted on a vertical axis 66. A sightsupport 7 is pivotally mounted on the axis 5, this support being preferably arranged at one side of the gun and carrying an adjustable sight-ring 1 and an adjustable sight. plate 8. :The angular position of the sight support 7 about its axis 5 is deter.- mined automatically in accordance with the angle of elevation of the gun, as will be hereinafter described. The sight-ring l is detachably mounted on a lever 9 which is pivotally mounted upon a horizontal shaft 10 the latter being mounted on the sight support 7. In' the present instance, the automatic positionlng of the sight-ring 1 is effected by. a parallel lever system com-' prising the levers 9 and 12, the link'll,

-the pivots 10 and 15 fixed to support 7, and

the movable pivots 1 3 and 14; said pivots correspondlng to the corners of a parallelogram, whereby for every angle of elevation of the gun the, sight-ring 1 is maintainedeXactly horizontal.

The lower arm of the lever 12, which is mounted on the sight support 7 by the pivot 15, carriesa pivot 17 to which is connected alink 18, the otherend of this link being pivotally connected to the gun support '33 by the pivot pin 19. The -pivots 5, 15, 17 and 19 form the corners or angles of a parallelogram, the pivots 5 and19 being titude of the target.

fixed, and the pivots 15 and 17 movable. The angular position of the lever 12 about its axis 5 is, by this latter parallelogram, determined automatically for every elevation of the gun.

The upwardly extending end of the lever 12 is provided with a pivot 20, a link 21 is connected at one end to this pivot, and the opposite end of said link is pivotally connected, at 2-2, to a rear sight slide 23, the latter being slidably mounted in a guide 24 on the sight support 7. A laterally proj ecting part of the slide is provided with the sight plate 8 having a sight opening 25. If desired, a suitable sight-glass can beapplied to the sight opening. By this construction it will be observed that an increase in the angle of elevation of the gun will cause the slide 23 to shift toward the muzzle of the gun, and, hence, the distance from the sightplate to the sighting ring will be correspondingly diminished. The parallel motion device and the cooperating parts are so proportioned that the deviation of the projectile, caused by the diminishing of the speed thereof, is partly compensated for by the dimi nution of the said distance, which causes the angle of the apex of the sight cone to be enlarged accordingly. A

As here inbefore stated, the position of the angle of elevation of the sight support 7 with respect to the angle of elevation of the gun 4 is automatically determined for the diilerent angles of elevation of the gun; that is to say, the declination of the sight-line is ad justed automatically for different elevations of the gun. For example, as indicated in F 9, at a higher elevation of the gun the angle (5 is smaller than the angle 3 at a lower elevation of the gun, and at an elevation of 90, 3 becomes 0. This automatic adjustment of the sighting device is accomplished by the following mechanism: At the rear end of the right support 7 is attached a pivot 26 on which is mounted a lever 27. The upper end 28 of this lever is provided with a pin or projection 29 ar' ranged to operate in a guide groove or slot 30 formed in the sight support 7, the curvature of the slot 30 being plotted according to known principles so as to give the proper angles of the sight support, and, hence, the slght-line relatively to the gun barrel for the different elevations of the gun at a given alof these grooves or slots 30 are provided, they being arranged one above another, each of these grooves or slots corresponding to a special target altitude. The guide pin 29 is inserted in the appropriate slot 30 which approximates most closely the altitude of the target. In the drawing four of these slots 30 are shown, corresponding to four predetermined altitudes.

It will be seen from Figs. 3 and 10 that, if

Preferabl. a number 7 the altitude of the target can be closely approximated, the target rangeor distance can be easily determined from the angle of the sight-line. To this end concentric scales may be applied to the sight support 7, as shown in Fig. 10, each of these scales being calibrated in accordance with a determined target altitude. The length of the upper arm 28 of the lever can be varied, as indicated in Fig. at, by fitting the upper end of this lever slidably on the body of the lever, in order to permit the'pin 29 of the arm to be inserted into one or the other of the slots 30.

From the above mentioned scales, the target distance can be directly determined according to the angle of the sight-line, taking into account the altitude of the target. This is of importance for an exact timing of the projectiles.

Preferably, and as shown in Fig. l, scales calibrated in accordance with different target distances are located along each slot 80, and the upper end 28 of the lever is shaped to form a pointer to cooperate with the scale for the slot in which the pin 29 is set to operate. For a determined target altitude, the pointer will then indicate directly the target distance or range for the corresponding angular position of the sight support 7. The lower portion 27 of the lever is pivotally connected with one end of a link 32, while the other end of the link 32 is connected to a pivot 3 L on the cradle of the gun. The pivot 34 is located vertically below the pivot 5, and the pivots 5, 26, 31 and 34 form the corners of a parallelogram of which the pivots 5 and 3% are fixed points and the pivots 26 and 31 are movable points. The lever 27 is therefore always maintained in a vertical position while the end 28 of this lever with the pin 29 thereon engaging the appropriate slot 30 regulates the angular position of the sight support and, in consequence, the angle of elevation of the sight-line.

By the construction of the sight-hole shown in Fig. 8, the observer is not hindered by the recoil of the gun, and, at the same time, the sight field viewed through the sight-opening is larger.

Instead of using a sight plate having an opening, a sight-ring having a small opening may be provided on the arm 36 of the slide 23, as shown in Fig. 3. By this construction, the observer may keep his eye at some distance to the rear of the opening 25 and, hence, will not be hindered by the recoil of the gun. Of course, the eye, the opening 25, and the front sight 2 must always be in a straight line. The observer then views the front sight 2 as a concentric ring around the ring 35 of the rear sight. Another ad vantage of this construction is that the eye views a larger field than is the case *where the observation is made through a smallopeningin the rear sight plate.

The mode of using a sighting device embodying the present invention is as follows:

The observer looking through the hole of the rear sight plate observes the constantly horizontal forward sight-ring as an ellipse, the vertical diameter ofwhich varies according to the angle of elevation of the gun. The angle of the-apex of the cone formed by imaginary lines through the eye of the observer and the sight-ring must be larger or smaller, according to the speed of the target, the angle of elevation of the sight-line, and the differences in the range or distance of the target. v

By the mechanism hereinbefore described, variations in the angle of elevation of the gun automatically produce appropriate alterations in the'angle of elevation of the'sight-angle, and at the same time the distance of the frontsight-ring from the eyepiece or rear. sight is also varied. The automatic adjustment of this distance is to compensate for the diminution of the velocity of the proj ectile the elevation of the gun is increased.

Sighting of the gun, is accomplished in the following way The gun is so pointed that the moving target appears to cross the sight-ring in the direction of the front sight. The aeroplane, which generally movesin a substantially horizontal plane, crosses the cone surface, forexample in line with the points 6 and f (Fig. 5), it passing the front sight at the moment that it in reality passes the point cl in the middle of the line bf. Instead of crossing the cone along the line blying in a vertical plane through the eye of the observer, the aeroplane can, of course, also cross the sight-cone along any other line, such, for example, as the line c-g.

The time required for the target to travel the distance (L -(Z, or any similar distance, such as bcl or cd, is constant, if the speed of the target and the target distance arecon-v stant; that is to say, the interval of time elapsing between the moment the observer sees the target passing the sight-ring andthe moment the target passes the front sight is always the same. If the target requires the same interval of time to move through the distance b-cZ that the projectile requires to reach the point d, the target will be hit at said point by the projectile fired at the moment the target passes the sight-ring.

According to the present invention, the

dimensions of the sight-ring and the dis- I tance of the sight-ring from the point 0 are determined in accordance with a ,predetermined speed of the projectile and a predetermined speed of the target, so that the time necessary for the projectile to travel over the curved trajectory 0- 05 and for the target to move over the distance Z20Z or,

any similar distance, such as ad, e-d or 00Z,-1s the same for a given target distance.

Allowance must be made for agreater or less target distance or-range and;for difference in the speed of the target, although the types of air-ships and-aeroplanes used in war-time move at approximately the same unchangeable speed, which-speed is known.-

In case such speed is not a usual one, it is necessary to estimate the speed. The diameter of the slght-rlng for a given target speed and-a given distance from the observers eye.

to the front sight can be easily determined from the speed average of the projectile for the-predetermined distance. The diminish by increasingthe angle of elevation of'the.

gun, the distance between the front sightring and eye is automatically diminished, in consequence of which the angle of the apex of the sight cone is increased. The period of time elapsing from the moment the target passes thesight-ring until the moment it passes the front sight is automatically varied so that it will equal the period of time re-v quired .by the projectile in reachingv the. target.

What is claimed is:

1. A sighting device for guns, comprising a gun support adapted to support a gun so as to occupy different angles of elevation, a sight support, a sight-ringand cooperating rear sight mounted on said sight support, and means operatively connected to the gun support and to said sight-ring for maintaining said sight-ring in a horlzontal planev for various angles of elevation of the gun.- '2. A sighting device for guns comprising'a gun support adapted to support a gun thereon to occupy diflerent angles of elevation, a sight support, a sight-ring and 00-. operating rear sight on said sight support, the sight ring being pivoted on a horizotal axis, and means operatively connecting the gun support and said sight-ring for maintaining said sightring in a horizontal plane irrespective of variations in the angle of elevation of the gun.

3. A sighting device for guns comprising a gun support adapted to support a gun thereon to occupy different angles of elevation, a sightsupport, a sightring and cooperative rear sight mounted on the sight support, and means embodying a parallel motion mechanism connecting the gun support and said sight-ring and operative to maintain the latter in a constant plane relatively to the horizontal irrespective of the angle of elevation of the gun.

4. A sighting device for guns comprising a gun support adapted to support a gun thereon to occupy different angles of elevation, a sight support, a front sight-ring and cooperative rear sight mounted on said sight support, and means connecting the gun support and one of said sights and operative to vary the distance between said sights in accordance with different angles'of elevation of the gun. V I

5. A sighting device for guns comprising a gun support adapted to support a gun thereon to occupy different angles of elevation, a sight support pivoted relatively to the gun support to swing in a plane parallel to the plane of elevation of the gun, front and rear sights carried on said sight support, and means connected to the gun support and to said sight support to swing the latter, relatively to the gun, into different angles of elevation in accordance with different angles of elevation of the gun.

6. A sighting device for guns comprising a gun support adapted to support a gun thereon to swing into diiferent angles of elevation, a sight support also mounted to swing relatively to the gun support into different angles of elevation and carrying sights, means connecting the gun support and the sight support for causing said sight support to swing into angles of elevation at variance with the angles of elevation of the gun, and means for altering. the angle of elevation of said sight support in accordance with variations in range of the target.

7. 'A. sighting device for guns comprising a gun support adopted to support. a gun thereon to swing into different angles of elevation, a sight support mounted to swing relatively to the gun support into different angles of elevation and carrying sights, and means connecting said gun support and-sight support for :causing said sight support to swing into different angles of elevation in accordance with different angles of elevation assumed by the gun, said means embodying an adjustment to allow for different target ranges, scales corresponding to the different target altitudes, and a pointer adapted to cooperate with the different scales to indicate the target ranges at the corresponding target altitudes. V

8. sighting device for guns comprising a gun support for supporting-a gun so as to swing into different angles of elevation, a sight support also mounted on the gun support so as to swing into different angles of elevation, a front sight on the sight support embodying a ring and a rear sight on said sight support to cooperate with said ring, one of said sights being shiftable relatively to the sight support in a direction toward and from the other sight to vary the angle of the apex of the cone of vision defined by said sights.

9. A sighting device for guns comprising a gun support for supporting a gun to swing into different angles of elevation, a sight support mounted on said gun support to swing into different angles of elevation, a front sight on said sight support embodying a ring, a rear sight on said sight support to cooperate with said ring, and means connected to the front sight to maintain the ring thereof in a constant horizontal plane irrespective of the angle of elevation of the sight support, one of said sights being movable relatively to the sight support in a direction toward and from the other sight to increase and diminish the angle of the apex of the cone of vision defined by said front sight.

10. A sighting device for guns comprising a gun support for supporting a gun to swing into difierent angles of elevation, a sight support mounted to swing relatively to said gun support into different angles of elevation, a front sight ring on said sight support, and a cooperating rear sight on said sight support, means connected to said gun support and said sight ring to maintain the latter constantly in a horizontal plane, and means connecting the gun support to said sight support for relatively shifting the sights to vary the distance between them in accordance with variations in the angle of elevation of the sight support.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

CASPER MELCHIOR BALTHAZAR VAN DEN BELD.

WVitnesses:

ANTONAI NAGTIGALL, N. C. VAN VEENER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C." 

